1. Field of the Invention
The present invention is generally related to a siphon pump for a marine propulsion device and, more particularly, to a siphon pump that uses a venturi device to remove water from under the cowl of an outboard motor.
2. Description of the Prior Art
Outboard motors are well known to those skilled in the art. Many types of outboard motors comprise idle relief exhaust ports which are used when the engine of the outboard motor is operating at low speed, such as idle speed. The venturi effect and the Bernoulli equation are well known to those skilled in the art of fluid dynamics.
U.S. Pat. No. 4,668,199, which issued to Freund et al on May 26, 1987, discloses an idle exhaust relief system for outboard motors. The exhaust system for an outboard motor includes a main exhaust passageway extending through a partially water filled chamber in the driveshaft housing. An inlet idle relief passage connects the top of the chamber with the main exhaust passageway and an outlet passage connects the top of the chamber with the atmosphere. The system thus defines an effective exhaust silencer for the idle exhaust.
U.S. Pat. No. 4,836,152, which issued to Riese on Jun. 6, 1989, discloses an exhaust heated crankcase for a 2-cycle marine engine. The idle exhaust pressure relief system in an outboard motor is utilized to simultaneously heat the engine crankcase and other parts of the fuel supply system to prevent the puddling of fuel typically occurring at lower engine temperatures. Because the idle exhaust pressure relief is inherently operable to conduct hot exhaust gases out of the exhaust manifold only at idle or low speed operation, heat is supplied to the crankcase only at temperatures when fuel puddling typically occurs.
U.S. Pat. No. 5,041,036, which issued to Clark et al on Aug. 20, 1991, describes an idle exhaust gas relief arrangement for an outboard motor. An outboard motor comprises an internal combustion engine including a lower surface having therein an exhaust gas discharge port, a driveshaft housing having an upper end including an upper face fixed to the lower surface of the internal combustion engine, an exhaust surface extending downwardly from the upper face, an interior vertically extending main exhaust gas passage extending from the upper face and communicating with the exhaust gas discharge port, an idle exhaust gas relief passage recessed in the upper face and in spaced relation to the main exhaust gas passage, and closed by the lower surface of the internal combustion engine, and an idle exhaust gas outlet port located in the outer surface and communicating with the idle exhaust gas relief passage. It also comprises an idle exhaust gas relief tube communicating between the main exhaust gas passage and the idle exhaust gas relief passage and having a portion extending vertically within the main exhaust gas passage and terminating in spaced relation above the water level in the driveshaft housing when the driveshaft housing is located in a normal operating position and when the driveshaft housing is at rest relative to the water.
U.S. Pat. No. 4,163,366, which issued to Kent on Aug. 7, 1979, describes an apparatus for disposal of leaking fluids in a turbofan engine. The invention relates to an apparatus which harmlessly purges all fluids which leak from the fittings of a turbofan aircraft engine. Purging is achieved by passing a low speed flow of ventilating air along the exterior walls of the engine combustor section. This is accomplished by enshrouding the engine core with a cylindrical cowl. A space between the cowl and the engine combustor makes an annular shaped cavity. Ports in the cowl allow air to be brought into the cavity from the bypass ducting of the engine. The rapidly moving volume of air thus brought in vaporizes any fuel which leaks into the cavity. The vaporized air/fuel mixture is then exhausted into the hot gas plume emitted from the rear of the core engine.
U.S. Pat. No. 5,927,338, which issued to Boticki et al on Jul. 27, 1999, describes a mixing eductor. An improved mixing eductor of the type wherein the primary liquid (e.g. water) is in a main stream flowing in a downstream direction is disclosed. A venturi tube is in the eductor and has an annular sharp edge in the main stream thereby dividing such stream into a primary stream and a secondary stream around the primary stream. The eductor has an air gap and a flow guide downstream thereof. In a specific embodiment, the flow guide is annular around the venturi tube and the tube and the guide are in spaced telescoped relationship. Several embodiments of the eductor and a new method for mixing liquids are disclosed.
U.S. Pat. No. 4,183,338, which issued to Lindberg on Jan. 15, 1980, describes a combustion control system adding a liquid, exhaust gases, and PCV gases. A combustion control system adds a fluid and heat energy to the air/fuel mixture of the induction system of an internal combustion engine in response to engine need to improve combustion, to increase power, to improve efficiency, and to reduce emissions. The system incorporates fluidic control mechanisms which provide the control functions without any moving parts. The system incorporates one or more variable impedance flow control mechanisms, each of which produces an impedance to flow through the control mechanism which varies in a controlled relationship to the pressure differential across the control mechanism. The system also incorporates a variable impedance siphon break in the line connecting the liquid source with the liquid-exhaust gas acceleration chamber.
U.S. Pat. No. 4,007,804, which issued to Hardison et al on Feb. 15, 1977, describes an apparatus for removal of condensation from a marine gas exploder device. Condensate accumulating in the combustion chamber of a marine gas exploder of the cylinder and piston type is collected by gravity flow in a sump formed in a cylinder side wall or in a face of the piston, depending upon whether the cylinder is oriented horizontally or vertically. One end of an exhaust tube is positioned adjacent the base of the sump so that gaseous combustion products flow through the sump into the exhaust tube so as to collect and remove the accumulated condensate.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
A fluid draining device for an outboard motor, made in accordance with the present invention, comprises a conduit having a first end and a second end, with the first end being connectable in fluid communication with an exhaust port of an engine. The conduit has a central portion connected in fluid communication between the first and second ends. The draining device further comprises a drain tube having a first end connected in fluid communication with the central portion. A second end of the drain tube is disposed at a region of the marine propulsion system from which water is to be drained.
In a particularly preferred embodiment of the present invention, the exhaust port of the engine is an idle relief exhaust port. The region of the marine propulsion system to be drained, in a preferred embodiment, is a surface of an adapter plate of the marine propulsion system on which water can form puddles in recesses of the adapter plate. A cowl is disposed over the engine of the marine propulsion system and the central portion of the conduit is disposed under the cowl. An opening is formed through the cowl and the opening is connected in fluid communication with the second end of the conduit.